Muirkirk is a parish, which lies in East Ayrshire Council Area, some 9 miles (15 km) west of Douglas in South Lanarkshire and 9 miles (15 km) northeast of Cumnock in East Ayrshire.
It is located in the old county of Ayrshire, which disappeared following the Local Government (Scotland) Act 1974.
The parish has an area of 123.1 sq. km (47.5 sq. miles). Muirkirk has 6 neighbouring parishes; namely Auchinleck, Avondale, Crawfordjohn, Douglas, Lesmahagow and Sorn.